Proton therapy was delivered to a volume of T2 hyper-intensity, contrast-enhancing regions, and surgical resection cavity with expansion of 1.5 cm. Total dose of 54 Gy/RBE in 30 fractions was delivered.

Additionally, radiation therapy to the brain may have considerable side effects, and treatment for LGG has been associated with impaired neuro-cognitive functioning.

The goal of management for LGG is to minimize toxicity, and one way to do this is to treat only patients at highest risk of progression following surgical resection. Numerous studies have attempted to identify high-risk features, however no consensus exists on which patients are truly at high risk of progression.

Another way to minimize toxicity to use a radiation technique that will spare as much normal tissue as possible. Proton therapy has the ability to provide this degree of normal tissue protection.

Although dosimetric studies of protons vs. photon therapy show substantial normal tissue sparing with protons, few studies document that the observed dosimetric advantages translate to a clinical benefit.

The authors of this study should be commended for compiling pilot data addressing this question, and their study suggests that proton therapy for LGG has a safety and efficacy profile similar to photon therapy in the acute setting, and potential for decreased neurocognitive toxicity in the long-term

The study was conducted with rigorous neuropsychiatric testing, and the outcomes of the cohort were well-characterized.

The study also paves the way for future potential studies of hypofractionation or dose escalation using proton therapy, techniques that could improve survival from LGG and may be more feasible with protons compared with photons.